How do I prevent MuseScore from listening to the MIDI input when it loses keyboard focus?

My usual wolkflow generally has me using a MuseScore window and a Reaper window at once; in Reaper I've got a recording loaded up which I'm studying or transcribing, and in MuseScore I'm notating my arrangement or my transcription.

Generally, I'll select a segment of audio in Reaper and play it, possibly on repeat, while I noodle around on my MIDI keyboard figuring out the pitches and harmonies, and then I'll pause Reaper, flip over to MuseScore, and enter some notes.

The problem is that if I leave MuseScore in note-input mode when Reaper has keyboard/mouse focus, then MuseScore will continue to listen to MIDI input and my score fills up with my noodlings.

Is there an easy way to make sure that when MuseScore loses keyboard focus, it will also automatically cease responding to MIDI?

It seems to be common sonse that if an application doesn't have keyboard/mouse focus, it should also be ignoring other user inputs as well; however, I can imagine cases where someone (not me!) would prefer the opposite behaviour, and so I'm figuring there must be a setting that I can set. But I haven't been able to find that setting.

(Obviously, toggling the MIDI button is not the answer I'm looking for!)

Thanks in advance!